Abstract: The process of the present invention is used to form resist features (22) having controlled predefined cross-sectional profiles, and is particular useful for forming features having reentrant profiles (24). In the process, a layer of a basic agent is formed on the substrate surface (20). Thereafter, a resist layer is formed on the layer of basic agent, causing at least a portion of the basic agent to diffuse into regions of the resist layer. The resist layer is exposed to radiant energy through a mask to form a patterned resist layer, which is developed to form resist features (22) having reentrant profiles (24) at those regions of the resist layer containing the diffused basic agent. The reentrant resist features (22) formed by the present method facilitates manufacture of magnetic heads, magnetoresistive sensors (102), and electronic components.